Powell, J. M..
Medieval monarchy and trade: the economic policy of emperor Frederick II of Sicily : (a survey) /
J.M. Powell 
. - Spoleto : Centro Italiano di studi sull'alto mediovo,  1962 
. - p. 421-524  24 cm. 
<br/><br/> У книзі дарчий напис автора. (Estr. dagli "Studi medievali" ; ser. 3 ; III, 2).
<br/><br/><label>Subjects--Personal Names: </label><br/>Frederick II II  Holy Roman Emperor and King of Sicily  1194-1250